This application is based upon and claims the benefit of Japanese Patent Application No. 2001-72448 filed on Mar. 14, 2001, the contents of which are incorporated herein by reference.
1. Field of the Invention
The present invention relates to electroluminescent devices (referred to herein as EL devices) that are used for various instruments of emissive-type segment displays and matrix displays, displays of various information terminals, and the like. The present invention also relates to methods for producing the same.
2. Related Art
An EL device is typically formed by laminating first electrodes, a first insulating layer, a luminescent layer, a second insulating layer, and second electrodes on an insulating glass substrate in this order. The first and the second insulating layers are made of silicon dioxide (SiO2), silicon nitride (SiN), silicon oxynitride (SiON), sitantalum pentaoxide (Ta2O5) or the like, and formed by sputtering, vapor deposition or the like.
It is, however, difficult to provide insulating layers that are formed by sputtering or vapor deposition with sufficient insulating performance (ability to withstand voltage) and sufficient water resistance over the entire area of the display panel of the EL device.
Therefore, to increase the insulating performance and the water resistance performance, JP-A-58-206095 and JP-A-10-308283 propose that the first and the second insulating layers have an aluminum oxide (Al2O3) and titanium oxide (TiO2) laminated structure (referred to as the Al2O3 and TiO2 laminated layer herein). The laminated structure is formed by alternately laminating Al2O3 layers and TiO2 layers by ALE (Atomic Layer Epitaxy).
In this case, each of the Al2O3 layers is an insulator, and each of the TiO2 layers is a semiconductor. Accordingly, the first and the second insulating layers have high insulating performance and high water resistance.
However, ALE involves stacking atomic layers one by one. Therefore, ALE for forming the first and the second insulating layers takes more time than sputtering or vapor deposition, which limits productivity.
It is therefore an object of the present invention to provide an EL device that fosters high productivity and a method that increases productivity.
To achieve the above-mentioned object, an EL device according to the present invention includes a first insulating layer made by a method other than ALE, for example, sputtering or vapor deposition, and a second insulating layer made by ALE. The second insulating layer covers an end surface of the first insulating layer.
Accordingly, the EL device has a high insulating performance and a high water resistance. Further, in this EL device, the total time for forming the first and the second insulating layers is reduced, which increases productivity.